WO2013065580A1

WO2013065580A1 - Display device

Info

Publication number: WO2013065580A1
Application number: PCT/JP2012/077625
Authority: WO
Inventors: 亮菊地; 知男高谷; 福島　浩
Original assignee: シャープ株式会社
Priority date: 2011-10-31
Filing date: 2012-10-25
Publication date: 2013-05-10
Also published as: US20140307188A1

Abstract

The purpose of the present invention is to improve the level of quality in external appearance of a display device where a switch panel for displaying a stripe image is arranged on the visible side of a main panel to allow a three dimensional image to be displayed, by making the inconsistencies in the gaps in the switch panel not easily noticeable. A liquid crystal display device is provided with: a main panel (2) for displaying an image; a switch panel (3) which is arranged on the visible side of the main panel (2) and displays a stripe image as a parallax barrier in order that the image displayed on the main panel (2) is viewed stereoscopically; a polarizing plate (4) which is arranged on the visible side of the switch panel (3) and converts incidence light to linearly polarized light; and a phase difference plate (7) which is arranged between the switch panel (3) and the polarizing plate (4) and converts the linearly polarized light to circularly polarized light while converting circularly polarized light to linearly polarized light.

Description

Display device

The present invention relates to a display device that displays a stripe image on a switch panel arranged on the viewing side of a main panel so that the image displayed on the main panel can be viewed as a three-dimensional image.

Conventionally, display devices capable of displaying an image in three dimensions by a so-called parallax barrier method are known. Such a display device has two liquid crystal panels arranged to face each other as disclosed in, for example, Japanese Patent Laid-Open No. 5-122733. The display device displays an image on one liquid crystal panel, and displays a black and white barrier stripe image (stripe image) on the other liquid crystal panel. Thereby, since the other liquid crystal panel functions as a parallax barrier, an image displayed on one liquid crystal panel can be visually recognized as a three-dimensional stereoscopic image. JP-A-5-122733 discloses a configuration in which a barrier / striped image is displayed on a liquid crystal panel arranged on the viewing side of two liquid crystal panels.

By the way, the panel arranged on the viewing side as described above has a pair of substrates and a seal portion arranged between the outer peripheral sides in a state where the pair of substrates are overlapped. In the panel, spacers are disposed between the pair of substrates so that the distance between the pair of substrates is constant in the surface direction.

However, in the panel having the above-described configuration, when the distance (gap) between the pair of substrates is not uniform in the surface direction, it may be visually recognized as gap unevenness. In particular, when a non-uniform gap occurs in the panel arranged on the viewing side, it becomes easy to be visually recognized as gap unevenness by reflected light of light incident from the viewing side.

An object of the present invention is to make it difficult to visually recognize gap unevenness of a switch panel in a display device in which a switch panel for displaying a stripe image is arranged on the viewing side of the main panel so that a three-dimensional image can be displayed. The purpose is to improve the appearance quality of the display device.

A display device according to an embodiment of the present invention is disposed as a parallax barrier so that an image displayed on a main panel that displays an image and a viewing side of the main panel can be viewed stereoscopically. A switch panel that displays a stripe image of the switch, a polarizing plate that is disposed on the viewing side of the switch panel and that converts incident light into linearly polarized light, and is disposed between the switch panel and the polarizing plate. And a retardation plate that converts linearly polarized light into circularly polarized light while converting circularly polarized light into linearly polarized light.

According to an embodiment of the present invention, in a display device in which a switch panel that displays a stripe image is arranged on the viewing side of a main panel so that a three-dimensional image can be displayed, gap unevenness of the switch panel is made difficult to see. be able to. Therefore, the appearance quality of the display device can be improved.

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a panel unit of a display device according to Embodiment 1 of the present invention. FIG. 2 is a plan view showing the arrangement of the seal portion of the switch panel. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4A is a plan view illustrating a schematic configuration of a counter substrate of the switch panel. FIG. 4B is a plan view showing a schematic configuration of the substrate of the switch panel. FIG. 5 is a graph showing the relationship between retardation and relative transmittance in the switch panel. FIG. 6 is a diagram illustrating polarization states of light incident from the viewing side and light reflected by the switch panel. FIG. 7 is a cross-sectional view showing how the light reflected by the switch panel is blocked by the polarizing plate. FIG. 8 is a diagram illustrating a change in chromaticity of the display device when Nz and polar angle of the retardation film are changed. FIG. 9A is a view corresponding to FIG. 4A in the switch panel of the display device according to the second exemplary embodiment. FIG. 9B is a view corresponding to FIG. 4B in the switch panel of the display device according to the second exemplary embodiment. FIG. 10A is a view corresponding to FIG. 4A in the switch panel of the display device according to the third embodiment. FIG. 10B is a view corresponding to FIG. 4B in the switch panel of the display device according to the third embodiment.

A display device according to an embodiment of the present invention is disposed as a parallax barrier so that an image displayed on a main panel that displays an image and a viewing side of the main panel can be viewed stereoscopically. A switch panel that displays a stripe image of the switch, a polarizing plate that is disposed on the viewing side of the switch panel and that converts incident light into linearly polarized light, and is disposed between the switch panel and the polarizing plate. And a retardation plate that converts linearly polarized light into circularly polarized light while converting circularly polarized light into linearly polarized light (first configuration).

With the above configuration, even when gap unevenness occurs in the switch panel arranged on the viewing side of the main panel, it is possible to suppress the gap unevenness from being visually recognized by light incident from the viewing side.

Specifically, on the viewing side of the switch panel, there are a polarizing plate that converts incident light into linearly polarized light, and a retardation plate that converts linearly polarized light into circularly polarized light while converting circularly polarized light into linearly polarized light. Has been placed. Thereby, the light incident from the viewing side is converted into linearly polarized light by the polarizing plate and then converted into circularly polarized light by the phase difference plate. Then, the circularly polarized light that is reflected by the switch panel and whose electric field vector rotation direction is reversed is incident on the retardation plate again, and the electric wave vector oscillation direction is polarized by the polarizing plate by the retardation plate. It is polarized into linearly polarized light that is 90 degrees different from the direction. This linearly polarized light is shielded by the polarizing plate. As a result, the reflected light incident from the viewing side and reflected by the switch panel is blocked by the polarizing plate. Therefore, it can suppress that the gap nonuniformity which arose in the switch panel is visually recognized by the viewer.

Therefore, the above-described configuration can improve the appearance quality of the display device.

In the first configuration, the switch panel includes a pair of substrates, a display medium disposed between the pair of substrates, and a seal portion for enclosing the display medium between the pair of substrates. And the polarizing plate and the retardation plate are arranged so as to cover the viewing side of the seal portion (second configuration).

In switch panels, the distance between the pair of substrates is often different between the periphery of the seal portion and the central portion of the substrate in plan view. That is, in the switch panel, gap unevenness is easily visible around the seal portion. Therefore, by disposing the polarizing plate and the phase difference plate so as to cover the viewing side of the seal part of the switch panel, the reflected light of the light incident from the viewing side can be shielded in the peripheral part of the seal part. . Thereby, the gap unevenness generated around the seal portion of the switch panel is not easily seen by the viewer.

In the second configuration, the switch panel is provided with a comb-like electrode on at least one of the pair of substrates (third configuration). In the switch panel having such a configuration, there are many simple panels having a spacer arranged between a pair of substrates to ensure a space between the substrates. Therefore, in the case of the switch panel having the above-described configuration, the gap between the pair of substrates is likely to be non-uniform, and gap unevenness is likely to occur. On the other hand, by applying the first and second configurations described above, even when gap unevenness occurs in the switch panel, the gap unevenness can be made difficult to visually recognize.

In any one of the first to third configurations, the retardation plate is disposed only on the viewing side of the switch panel (fourth configuration). By doing so, only the light incident from the viewing side of the switch panel and reflected by the switch panel can be shielded by the polarizing plate and the retardation plate.

In any one of the first to fourth configurations, the retardation plate has an Nz smaller than 1 (fifth configuration). When converted to circularly polarized light in the display device, the dependence on the viewing angle direction is greater than when converted to linearly polarized light. For this reason, the change in color tone increases depending on the direction in which the viewer visually recognizes. Therefore, as described above, by changing Nz of the retardation plate to Nz smaller than Nz (Nz is 1 or more) of a retardation plate usually used for a liquid crystal panel, the change in color depending on the viewing direction can be achieved. Can be suppressed. Accordingly, in the display device, it is possible to suppress a deterioration in display quality that occurs when light is converted into circularly polarized light.

In any one of the first to fifth configurations, the switch panel has a retardation of 380 nm to 440 nm (sixth configuration). Thereby, the transmittance | permeability of a switch panel can be aimed at. Therefore, when displaying a three-dimensional image using a switch panel, display quality can be improved.

Hereinafter, preferred embodiments of the display device of the present invention will be described with reference to the drawings. In addition, the dimension of the structural member in each figure does not represent the dimension of an actual structural member, the dimension ratio of each structural member, etc. faithfully.

[Embodiment 1]
(overall structure)
FIG. 1 shows a schematic configuration of a panel module 1 of a liquid crystal display device (display device) according to an embodiment of the present invention. The panel module 1 is configured by stacking a plurality of members in the thickness direction. Specifically, the panel module 1 includes a main panel 2 that displays an image, a switch panel 3 that displays a slit-shaped black and white image (stripe image), and the main panel 2 and the switch panel 3 sandwiched therebetween. Three

polarizing plates

4, 5 and 6 are provided. The switch panel 3 is located on the viewing side of the main panel 2. Although not particularly illustrated, a backlight is disposed on the back surface (the side opposite to the viewing side) of the panel module 1.

As shown in FIG. 1, in the panel module 1, a polarizing plate 4, a retardation plate 7, a switch panel 3, a polarizing plate 5, a main panel 2, and a polarizing plate 6 are laminated in order from the viewing side (upper side in FIG. 1). ing. In the panel module 1, the switch panel 3 and the main panel 2 to which the polarizing plate 5 is attached are bonded by an adhesive 8. Thereby, the switch panel 3 and the main panel 2 are united.

The liquid crystal display device according to the present embodiment forms a parallax barrier by displaying a stripe image on the switch panel 3, and among the images displayed on the main panel 2, the image for the right eye is only for the right eye, and for the left eye. This is a so-called parallax barrier type three-dimensional image display device that makes each image visible only to the left eye. Therefore, the main panel 2 displays the left-eye image and the right-eye image on one screen in synchronization with the display of the stripe image on the switch panel 3. When the liquid crystal display device according to the present embodiment is used as a two-dimensional image display device, driving of the switch panel 3 is stopped to make the switch panel 3 transparent.

The main panel 2 is, for example, a VA (Vertical Alignment) type liquid crystal panel. The main panel 2 includes an active matrix substrate 11 in which a large number of pixels are arranged in a matrix, and a counter substrate 12 disposed to face the active matrix substrate 11. The main panel 2 includes a liquid crystal layer 13 between the active matrix substrate 11 and the counter substrate 12 that can be switched between a birefringent state and a light transmission state.

In the active matrix substrate 11, a plurality of TFTs (Thin Film Transistors; not shown), pixel electrodes, and a plurality of wirings (source wiring, gate wiring, etc.) are provided on a transparent substrate such as a glass substrate. Note that the configuration of the TFT is the same as the conventional one, and thus detailed description thereof is omitted.

The pixel electrode is a transparent electrode and is formed of a light-transmitting conductive material such as ITO (indium tin oxide). The pixel electrodes are spaced apart from each other for each pixel. The pixel electrode defines a pixel as a unit of image display.

Although not particularly illustrated, the source electrode, the gate electrode, and the drain electrode of the TFT are connected to the source wiring, the gate wiring, and the pixel electrode, respectively. The point that a signal is input to the TFT via the gate wiring and the source wiring and the TFT is driven is the same as that of the conventional liquid crystal display device, and thus detailed description is omitted.

In the counter substrate 12, a counter electrode made of a transparent conductive film such as ITO is provided on a transparent substrate such as a glass substrate. The counter substrate 12 is provided with RGB color filters.

In the main panel 2 configured as described above, by controlling the electric field applied to the liquid crystal layer 13, that is, the voltage applied between the counter electrode and the pixel electrode, the liquid crystal layer 13 is combined with the light transmission state and the light. Switching to a state of refraction can be performed in units of pixels. That is, by controlling the application of the electric field to the liquid crystal layer by the TFT, when light passes through the light transmission region of the liquid crystal layer 13, the region colored by the color filter is displayed as a color image.

In the present embodiment, the color filter is provided on the counter substrate 12. However, the present invention is not limited to this, and a configuration without a color filter may be used.

(Switch panel)
As shown in FIGS. 1, 3, 4 </ b> A, and 4 </ b> B, the switch panel 3 includes a substrate 21 and a counter substrate 22 disposed to face the substrate 21. As shown in FIG. 4B, a comb-like electrode 21a having a plurality of slits extending in one direction of the substrate 21 (in the direction of the short side of the substrate 21 in the example of FIG. 4B) is formed on the substrate 21. . On the other hand, a common electrode 22 a having a rectangular shape smaller than the counter substrate 22 is formed on the counter substrate 22. Further, as shown in FIGS. 1 and 3, the switch panel 3 includes a liquid crystal layer 23 that is capable of switching between a light rotating state and a light transmitting state between a substrate 21 and a counter substrate 22.

As shown in FIGS. 2 and 3, the switch panel 3 is provided with a seal portion 24 between the substrate 21 and the counter substrate 22 on the outer peripheral side thereof. The seal portion 24 is made of, for example, an epoxy resin, and is provided along the outer periphery of the substrate 21 and the counter substrate 22. By providing the seal portion 24 between the substrate 21 and the counter substrate 22, a sealed space can be formed between the substrate 21 and the counter substrate 22. By sealing liquid crystal (display medium) in this space, the above-mentioned liquid crystal layer 23 is formed.

The switch panel 3 is provided with a plurality of spacers (not shown) inside the seal portion 24 so that the distance between the substrate 21 and the counter substrate 22 is uniform in the surface direction. As will be described later, in the switch panel 3, even when the spacer is arranged between the substrate 21 and the counter substrate 22 in this way, it is difficult to make the distance between the substrate 21 and the counter substrate 22 constant in the surface direction. , The interval varies.

Further, although not particularly illustrated, in the substrate 21 and the counter substrate 22 of the switch panel 3, an alignment film is provided on the surface on the liquid crystal layer 23 side. These alignment films are rubbed so that the surface is rubbed in one direction with a cloth or the like. By performing the rubbing process on the alignment film in this manner, the liquid crystal molecules in the liquid crystal layer 23 can be aligned in a certain direction. In the present embodiment, the alignment films of the substrate 21 and the counter substrate 22 are parallel to each other when the rubbing direction of the alignment film provided on the substrate 21 and the rubbing direction of the alignment film provided on the counter substrate 22 are viewed from the viewing side. As rubbed.

In FIGS. 4A and 4B, the rubbing directions of the substrate 21 and the counter substrate 22 are indicated by hatched arrows, respectively. In the example of FIG. 4B, if the lines extending in the horizontal direction (dashed lines) are the reference lines of 0 degrees and 180 degrees, the rubbing direction of the alignment film on the substrate 21 side is inclined 72 degrees clockwise (in FIG. 4B). -72 degrees). On the other hand, as shown in FIG. 4A, the rubbing direction of the alignment film on the counter substrate 22 side is 180 degrees different from the rubbing direction of the alignment film on the substrate 21 side (108 degrees in FIG. 4A).

In this way, the alignment films of the substrate 21 and the counter substrate 22 sandwiching the liquid crystal layer 23 are each subjected to a rubbing process so that the rubbing directions are parallel to each other, thereby causing the liquid crystal molecules in the liquid crystal layer 23 to have their long axes. It can arrange | position so that a direction may become the same direction.

The substrate 21 of the switch panel 3 may have any configuration as long as it can display a stripe image on the switch panel 3, such as an active matrix substrate in which a large number of pixels are arranged in a matrix. There may be.

In the switch panel 3 according to the present embodiment, it is preferable that the liquid crystal of the liquid crystal layer 23 has a retardation dΔN (cell thickness × birefringence) of 380 nm to 440 nm. Here, when the retardation of the switch panel 3 is changed, the ratio of the transmittance of the switch panel 3 to the transmittance when white display is performed with the TN liquid crystal (hereinafter referred to as relative transmittance) is a characteristic as shown in FIG. Have As shown in FIG. 5, the relative transmittance is maximum when the retardation of the switch panel 3 is about 410 nm, and a parabola with the relative transmittance at the top when the retardation is about 410 nm is drawn. In such characteristics, in order to obtain a contrast close to that of a TN liquid crystal, a retardation range in which the relative transmittance is 95% or more (380 nm to 440 nm, that is, a range indicated by an arrow in FIG. 5) is preferable.

The

polarizing plates

4, 5, and 6 shown in FIG. 1 are configured so that only components in a specific direction among light components in each direction can pass. That is, the

polarizing plates

4, 5, and 6 are configured to convert incident light into linearly polarized light. The

polarizing plates

5 and 6 have absorption axes corresponding to the characteristics of the main panel 2 in order to convert light passing through the main panel 2 into linearly polarized light. The polarizing plate 4 has an absorption axis corresponding to the characteristics of the switch panel 3 in order to convert light passing through the switch panel 3 into linearly polarized light.

In the case of this embodiment, the polarizing plate 6 disposed on the viewing side of the switch panel 3 is configured so that the angle of the absorption axis is, for example, 63 degrees. And the polarizing plate 5 arrange | positioned with respect to the main panel 2 at the switch panel 3 side is comprised so that the angle of an absorption axis may be 153 degree | times. Here, the angle of the absorption axis is a positive value when the panel is viewed from the viewing side and tilted counterclockwise with respect to the horizontal direction.

As shown in FIG. 1, a retardation plate 7 is disposed between the polarizing plate 4 located on the viewing side of the panel unit 1 and the switch panel 3. The retardation plate 7 is configured to convert the incident linearly polarized light into circularly polarized light, and to convert the circularly polarized light into linearly polarized light when the circularly polarized light is incident. That is, the phase difference plate 7 is a λ / 4 phase difference plate that can shift the phase of two orthogonal polarization components by ¼ wavelength. The absorption axis of the phase difference plate 7 is inclined 45 degrees clockwise with respect to the absorption axis of the polarizing plate 4 when the panel unit 1 is viewed from the viewing side. In this way, by shifting the angle between the absorption axis of the retardation film 7 and the absorption axis of the polarizing plate 45 by 45 degrees, linearly polarized light is converted into circularly polarized light whose electric field vector rotates in a circular shape in the retardation film 7. Can be converted.

As will be described later, the retardation film 7 has a parameter Nz (= (ns−nz) / (ns−nf)) representing the degree of biaxiality of the birefringent layer that is smaller than 1.0. Preferably it is configured. Here, in the above formula of Nz, nz represents the refractive index in the thickness direction of the retardation plate 7, ns represents the refractive index in the slow axis direction, and nf represents the refractive index in the fast axis direction.

Thus, by arranging the polarizing plate 4 and the retardation plate 7 in order from the viewing side, the light incident from the viewing side is converted into linearly polarized light by the polarizing plate 4 as shown in the column of external light incidence in FIG. Then, the linearly polarized light can be converted into circularly polarized light by the phase difference plate 7. As shown in the column of external light reflection in FIG. 6, the light reflected by the switch panel 3 is incident on the phase difference plate 7 as circularly polarized light, and is thus converted into linearly polarized light by the phase difference plate 7.

By the way, in the switch panel 3, as described above, a gap (gap) is provided between the substrate 21 and the counter substrate 22 by disposing the seal portion 24 and a spacer (not shown) between the substrate 21 and the counter substrate 22. Is formed. In the switch panel having such a configuration, it is difficult to make the seal portion 24 and the spacer have the same dimension in the thickness direction. Therefore, the center portion and the peripheral portion of the seal portion 24 are viewed in plan view of the switch panel 3. The gap is likely to vary. Thereby, when the viewer visually recognizes the panel unit 1, gap unevenness is easily visually recognized in the peripheral portion of the seal portion 24 of the switch panel 3 positioned on the viewer side. This is because light incident from the viewing side is reflected by the switch panel 3 and the reflected light is visually recognized by the viewer.

In particular, when the main panel 2 and the switch panel 3 are bonded to each other with the adhesive 8, a tensile force acts on the outer peripheral side portion of the switch panel 3 in the surface direction when the adhesive 8 is dried. Then, the gap changes on the outer peripheral side of the switch panel 3, and the gap unevenness is more easily recognized around the seal portion 24.

On the other hand, as in the configuration of the present embodiment, the polarizing plate 4 and the phase difference plate 7 are arranged in this order from the viewing side on the viewing side of the switch panel 3 so that the light is incident from the viewing side and reflected by the switch panel 3 The light can be shielded by the retardation plate 7 and the polarizing plate 4 (see FIG. 7). That is, as described above, light incident from the viewing side of the panel unit 1 is converted into linearly polarized light by the polarizing plate 4 and then converted into circularly polarized light by the phase difference plate 7 (see FIG. 6). At this time, the phase difference plate 7 converts the light into circularly polarized light whose electric field vector rotates clockwise. The light converted into circularly polarized light is reflected by the switch panel 3 to become circularly polarized light whose electric field vector rotates counterclockwise, and is incident on the phase difference plate 7. In this phase difference plate 7, circularly polarized light whose electric field vector rotation direction is counterclockwise is converted into linearly polarized light whose polarization direction is 90 degrees different from the linearly polarized light obtained by the polarizing plate 4. Thereby, the light converted into the linearly polarized light by the phase difference plate 7 is shielded by the polarizing plate 4.

Therefore, with the above-described configuration, the light incident from the viewing side of the panel unit 1 and reflected by the switch panel 3 is shielded by the polarizing plate 4 and the phase difference plate 7. Therefore, it is possible to prevent the viewer from visually recognizing gap unevenness of the switch panel 3.

As described above, when circularly polarized light is used, the dependence on the viewing angle direction is larger than that of a panel using linearly polarized light. Therefore, depending on the viewing angle direction, the color may change greatly. FIG. 8 shows changes in chromaticity when the polar angle (an angle inclined toward the panel with respect to the normal direction of the panel) is changed. In FIG. 8, when Nz of the phase difference plate 7 is changed to Nz = 0.1, 1.0, 1.6, the color when the panel unit 1 is viewed from all directions with the polar angle changed. It shows the change in degree. In each graph shown in FIG. 8, the chromaticity coordinate X is on the horizontal axis, and the chromaticity coordinate Y is on the vertical axis.

As can be seen from FIG. 8, as the polar angle increases, the change in chromaticity also increases and the color changes greatly. Further, the smaller the Nz of the phase difference plate 7, the smaller the change in chromaticity when the polar angle is large (80 degrees in the example of FIG. 8). That is, the smaller the Nz of the phase difference plate 7, the more the color change can be suppressed. In particular, when Nz of the phase difference plate 7 is smaller than Nz (Nz = 1) of a phase difference plate used in a general liquid crystal display device, a change in color is further suppressed even if the polar angle is increased. be able to.

Next, switching between 2D display and 3D display of the panel unit 1 having the above-described configuration will be described.

In the case of two-dimensional display, since no voltage is applied to the liquid crystal layer 23 of the switch panel 3, the phase of light can be changed by λ / 2 by the retardation of the switch panel 3 and the retardation plate 7. As a result, light that has been emitted from a backlight (not shown) and then converted to linearly polarized light by the

polarizing plates

5 and 6 is polarized by the switch panel 3 and the phase difference plate 7 so as to be parallel to the transmission axis of the polarizing plate 4. The direction can be changed. The light whose polarization direction has been changed in this way passes through the polarizing plate 4 to the viewing side. Therefore, the viewer can visually recognize the image displayed on the main panel 2 as a two-dimensional image. Note that, as described above, the absorption axes of the polarizing plate 5 and the polarizing plate 7 are shifted by 90 degrees.

On the other hand, in the case of three-dimensional display, a voltage is applied to the portion of the liquid crystal layer 23 of the switch panel 3 where the stripe image is displayed, so that the liquid crystal molecules in the liquid crystal layer 23 rise. If it does so, the light which injected into this switch panel 3 by the switch panel 3 and the phase difference plate 7 will inject into the polarizing plate 7, without changing a polarization direction. Thereby, in the part which displays a striped image in the switch panel 3, since it light-shields by the polarizing plate 7, it becomes black display. On the other hand, since no voltage is applied to the liquid crystal layer 23 of the switch panel 3 other than the portion where the stripe image is displayed, light passes through the polarizing plate 7 as in the case of the above-described two-dimensional display. As described above, a stripe image can be displayed on the switch panel 3.

(Effect of Embodiment 1)
In the present embodiment, in the configuration in which the switch panel 3 is arranged on the viewing side of the main panel 2, the polarizing plate 4 that converts incident light into linearly polarized light and the circularly polarized light are further circularly connected to the viewing side of the switch panel 3. A phase difference plate 7 for converting to polarized light is disposed. Thereby, even if the light incident from the viewing side of the panel unit 1 is reflected by the switch panel 3, the reflected light can be shielded by the polarizing plate 4 and the phase difference plate 7. That is, light incident from the viewing side of the panel unit 1 is converted into linearly polarized light by the polarizing plate 4 and then converted into circularly polarized light by the phase difference plate 7. When reflected by the switch panel 3, the electric field vector becomes circularly polarized light that rotates in the opposite direction. The circularly polarized light is converted by the phase difference plate 7 into linearly polarized light having a polarization direction different by 90 degrees from the linearly polarized light converted by the polarizing plate 4. Thereby, the linearly polarized light converted by the phase difference plate 7 is shielded by the polarizing plate 4.

With the above-described configuration, gap unevenness due to gap variation between the substrate 21 and the counter substrate 22 in the switch panel 3 is less likely to be visually recognized. Therefore, the appearance quality of the liquid crystal display device can be improved.

Also, by setting Nz of the retardation film 7 to a value smaller than 1, it is possible to suppress changes in the color of the image when circularly polarized light as described above is used. Thereby, the display quality of the liquid crystal display device can be improved.

[Embodiment 2]
9A and 9B show schematic configurations of the substrate 51 and the counter substrate 52 in the switch panel of the liquid crystal display device according to Embodiment 2 of the present invention. In the second embodiment, the configuration of the switch panel is different from the configuration of the first embodiment. Below, the same code | symbol is attached | subjected to the structure same as Embodiment 1, and description is abbreviate | omitted, and only a different part from Embodiment 1 is demonstrated.

In this embodiment, the panel unit is used in a state where the long side of the switch panel shown in FIGS. 9A and 9B is positioned up and down. Therefore, a comb-tooth electrode 51a having a plurality of slits extending in the longitudinal direction of the switch panel is formed on the substrate 51 of the switch panel. The counter substrate 52 is formed with a rectangular common electrode 52a, similar to the counter substrate 22 in the first embodiment.

In the switch panel of this embodiment, the rubbing directions of the substrate 51 and the counter substrate 52 are directions indicated by arrows in FIGS. 9A and 9B. That is, in the example of FIG. 9B, when the alternate long and short dash line is a reference line of 0 degrees and 180 degrees, the rubbing direction of the alignment film on the substrate 51 side is inclined by 18 degrees counterclockwise. On the other hand, as shown in FIG. 9A, the rubbing direction of the alignment film on the counter substrate 52 side is 180 degrees different from the rubbing direction on the substrate 51 side (−162 degrees).

Therefore, in the above example, the retardation plate 7 disposed on the viewing side of the switch panel has an absorption axis angle of −252 degrees, and the polarizing plate 4 disposed on the viewing side of the retardation plate 7 is The angle of the absorption axis is -207 degrees.

Even in the above configuration, light incident from the viewing side of the switch panel can be converted into linearly polarized light by the polarizing plate 4, and the linearly polarized light can be converted into circularly polarized light by the phase difference plate 7. Then, the circularly polarized light reflected by the switch panel is converted by the phase difference plate 7 into linearly polarized light having a polarization direction different from that of the linearly polarized light obtained by the polarizing plate 4 by 90 degrees. Thus, the linearly polarized light converted from the circularly polarized light by the phase difference plate 7 is shielded by the polarizing plate 4.

(Effect of Embodiment 2)
In this embodiment, a comb-tooth electrode 51a having a plurality of slits extending in the longitudinal direction is formed on the substrate 51 of the switch panel. Then, the rubbing directions of the substrate 51 and the counter substrate 52 were set to 18 degrees and −162 degrees, respectively, for example, as shown in FIGS. 9A and 9B. Even in such a configuration, the angle of the absorption axis of the phase difference plate 7 disposed on the viewing side of the switch panel and the angle of the absorption axis of the polarizing plate 4 disposed on the further viewing side of the phase difference plate 7 are opposed to each other. By setting the substrate 52 so as to have the same relationship as that of the first embodiment with respect to the rubbing direction of the substrate 52, the same effects as those of the first embodiment can be obtained. That is, also in this embodiment, the reflected light of the switch panel can be shielded by the polarizing plate 4 and the phase difference plate 7, and the gap unevenness of the switch panel can be made difficult to visually recognize.

[Embodiment 3]
FIG. 10 shows a schematic configuration of the substrate 61 and the counter substrate 62 in the switch panel of the liquid crystal display device according to Embodiment 3 of the present invention. In the second embodiment, the configuration of the switch panel is different from the configuration of the first embodiment. Below, the same code | symbol is attached | subjected to the structure same as Embodiment 1, and description is abbreviate | omitted, and only a different part from Embodiment 1 is demonstrated.

In this embodiment, the panel unit is used either in a state where the long side of the switch panel shown in FIG. 10 is positioned up and down (the state shown in FIG. 10) or in a state where the short side is positioned up and down. In other words, the panel unit in this embodiment is configured to be able to display an image in three dimensions, regardless of whether the long side is positioned vertically or horizontally.

The switch panel substrate 61 is formed with comb-shaped electrodes 61a having a plurality of slits extending along the short sides of the switch panel. On the counter substrate 62, comb-shaped electrodes 62a having a plurality of slits extending in the longitudinal direction of the switch panel are formed. That is, in this embodiment, comb electrodes are formed on both the substrate 61 and the counter substrate 62 of the switch panel. In addition, the comb-tooth electrode 61a formed on the substrate 61 and the comb-tooth electrode 62a formed on the counter substrate 62 are formed so as to be orthogonal to each other when viewed from the viewing direction of the switch panel.

Thereby, in a state where the long side of the switch panel is positioned up and down (state of FIG. 10), a stripe image is obtained by the comb-tooth electrode 61a on the substrate 61 side. On the other hand, in the state where the short side of the switch panel is positioned up and down, a stripe image is obtained by the comb-tooth electrode 62 a of the counter substrate 62.

Note that the rubbing directions of the switch panel substrate 61 and the counter substrate 62 in this embodiment are the same as those in the first embodiment. Therefore, the angle of the absorption axis of the polarizing plate arranged on the viewing side of the switch panel and the angle of the absorption axis of the phase difference plate are the same as in the case of the first embodiment.

Even in the above configuration, light incident from the viewing side of the switch panel can be converted into linearly polarized light by the polarizing plate 4, and the linearly polarized light can be converted into circularly polarized light by the phase difference plate 7. The circularly polarized light reflected by the switch panel is converted by the phase difference plate 7 into linearly polarized light having a polarization direction different from that of the linearly polarized light obtained by the polarizing plate 4 by 90 degrees. Thus, the linearly polarized light converted from the circularly polarized light by the phase difference plate 7 is shielded by the polarizing plate 4.

(Effect of Embodiment 3)
In this embodiment,

comb electrodes

61a and 62a each having a plurality of slits extending in directions orthogonal to each other when viewed from the viewing direction of the switch panel are formed on the substrate 61 and the counter substrate 62 of the switch panel. As a result, three-dimensional display is possible even when the panel unit is turned upside down. Even in such a configuration, as in the first embodiment, the polarizing plate 4 that can convert incident light into linearly polarized light and the phase plate 7 that can convert linearly polarized light into circularly polarized light are provided on the viewing side of the switch panel. By providing each, it is possible to block the reflected light of the switch panel. Therefore, the gap unevenness of the switch panel can be made difficult to visually recognize.

[Other Embodiments]
While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and can be implemented by appropriately modifying the above-described embodiment without departing from the spirit thereof.

In each of the above embodiments, a VA liquid crystal panel is used as the main panel. However, the main panel may be another type of liquid crystal panel such as an IPS (In-Plane Switching) type or a TN type.

In each of the embodiments, a liquid crystal panel is used as the switch panel 3 and the main panel 2. However, the switch panel 3 and the main panel 2 may be configured by a display panel other than the liquid crystal panel as long as an image can be viewed in three dimensions by two panels.

The display device according to the present invention has a switch panel on the viewing side of the main panel and can be used for a display device capable of displaying a three-dimensional image.

Claims

A main panel displaying images,
A switch panel that is disposed on the viewing side of the main panel and displays a stripe image as a parallax barrier so that an image displayed on the main panel can be seen in three dimensions;
A polarizing plate that is disposed on the viewing side of the switch panel and converts incident light into linearly polarized light,
A display device, which is disposed between the switch panel and the polarizing plate, and includes a retardation plate that converts linearly polarized light into circularly polarized light while converting circularly polarized light into linearly polarized light.
The switch panel includes a pair of substrates, a display medium disposed between the pair of substrates, and a seal portion for enclosing the display medium between the pair of substrates,
The display device according to claim 1, wherein the polarizing plate and the retardation plate are disposed so as to cover a viewing side of the seal portion.
The display device according to claim 2, wherein the switch panel is provided with a comb-like electrode on at least one of the pair of substrates.
The display device according to any one of claims 1 to 3, wherein the phase difference plate is disposed only on a viewing side of the switch panel.
The display device according to any one of claims 1 to 4, wherein the retardation plate has Nz smaller than 1.0.
The display device according to any one of claims 1 to 5, wherein the switch panel has a retardation of 380 nm to 440 nm.